# -*- coding: utf-8 -*-
"""
通信适配器抽象基类
所有中间件适配器必须继承此类并实现全部抽象方法
遵循 Factory + Strategy 模式
"""

import asyncio
import logging
from abc import ABC, abstractmethod
from dataclasses import dataclass
from typing import Callable, Awaitable, List, Optional

from uas.comm.message import Message

logger = logging.getLogger(__name__)

# 消息处理器类型：同步 or 异步均可
MessageHandler = Callable[[Message], Optional[Awaitable[None]]]


@dataclass
class ConnectionConfig:
    """通用连接配置（由 URL 解析填充）"""
    scheme:   str            # redis / kafka / dds
    host:     str   = "localhost"
    port:     int   = 0
    username: str   = ""
    password: str   = ""
    database: str   = ""     # redis db index / kafka group id / dds domain
    options:  dict  = None   # URL query 参数

    def __post_init__(self):
        if self.options is None:
            self.options = {}


class CommBaseAdapter(ABC):
    """
    所有通信适配器的抽象基类
    子类只需实现以下 5 个核心方法
    """

    def __init__(self, config: ConnectionConfig):
        self.config   = config
        self.logger   = logging.getLogger(self.__class__.__name__)
        self._running = False
        self._handlers: dict[str, List[MessageHandler]] = {}

    # ── 生命周期 ──────────────────────────────────────────────────

    @abstractmethod
    async def connect(self) -> None:
        """建立连接"""
        ...

    @abstractmethod
    async def disconnect(self) -> None:
        """断开连接"""
        ...

    @property
    def is_connected(self) -> bool:
        return self._running

    # ── 核心功能 ──────────────────────────────────────────────────

    @abstractmethod
    async def publish(self, message: Message) -> bool:
        """
        发布消息到指定 topic
        :return: True 表示发送成功
        """
        ...

    @abstractmethod
    async def subscribe(self, topic: str, handler: MessageHandler) -> None:
        """
        订阅 topic，注册消息处理回调
        支持通配符（由各适配器自行实现）
        """
        ...

    @abstractmethod
    async def unsubscribe(self, topic: str) -> None:
        """取消订阅"""
        ...

    # ── 可选扩展 ──────────────────────────────────────────────────

    async def request(self, message: Message, timeout: float = 5.0) -> Optional[Message]:
        """
        Request/Reply 模式（默认未实现，子类可覆盖）
        """
        raise NotImplementedError(f"{self.__class__.__name__} 不支持 Request/Reply 模式")

    async def health_check(self) -> bool:
        """健康检查，默认返回连接状态"""
        return self._running

    # ── 内部工具 ──────────────────────────────────────────────────

    def _register_handler(self, topic: str, handler: MessageHandler):
        self._handlers.setdefault(topic, []).append(handler)

    async def _dispatch(self, message: Message):
        """将消息分发给所有匹配的 handler"""
        handlers = self._handlers.get(message.topic, [])
        for handler in handlers:
            try:
                result = handler(message)
                if asyncio.iscoroutine(result):
                    await result
            except Exception as e:
                self.logger.error(f"Handler 执行异常 topic={message.topic}: {e}", exc_info=True)

    async def __aenter__(self):
        await self.connect()
        return self

    async def __aexit__(self, *args):
        await self.disconnect()